Sustainable development of chitosan-gelatin composite films for food packaging using crude chitosan extracted from American lobster (Homarus americanus) shell waste

Abstract

In this study, crude chitosan extracted from American lobster shells (Homarus americanus) was used to develop bio-based films. These films were prepared using solvent casting at various drying temperatures (37, 60, and 80 °C) and enhanced by blending with sunflower oil and gelatin from fish skin. Structural and thermal analyses (FT-IR, XRD, and TGA) demonstrated excellent compatibility between the extracted chitosan and fish gelatin. A 1:1 blend of these biopolymers resulted in films with increased flexibility and reduced water vapor permeation compared to pure chitosan films. Adding 10 % (w/w polymer) sunflower oil improved surface hydrophobicity and reduced swelling without compromising strength. Higher drying temperatures increased swelling, stretchability, and opacity, but decreased tensile strength and vapor permeability. Films prepared at 80 °C exhibited the best elasticity (100.4 %) and the lowest vapor permeability (1.2 g.mm/kPa.h.m²) while maintaining adequate tensile strength (27 MPa). This study demonstrates a sustainable approach for developing chitosan-gelatin composite films using renewable marine processing byproducts. In particular, the applicability of crude chitosan extracted from waste lobster shells (without additional purification steps) as a cost-effective and sustainable feedstock is highlighted, offering an eco-friendly alternative to conventional plastic food packaging.